Supersede

On Usenet, the process of posting a new message that replaces a previous one. Most clients won't let you do this unless they believe that you are the person that wrote the original, in order to reduce abuse. However, it is fairly trivial to forge a supersede header.

Fascinatingly, by far the most common error in creating a forged supersede is to spell it supercede.

Superseding a message is effectively equivalent to posting a cancel followed by a new message, but is accomplished in a single message. Like cancels, many servers do not honour supersedes due to large-scale abuse.